Replace non standard characters in php - php

Question

I'm trying to replace some non standard characters like ë,Ë,ç,Ç with numeric entities like Ë , ' etc but i ran into a bit of a problem.
When i try to replace them directly like this it works fine:
$string = "Ë";
$vname = str_replace("Ë","AAAA",$string);
echo $vname."<br>";
an i get AAAA as a result.
But when i try to replace the characters from a string that i get from a form with POST then it doesn't change the characters. Here is an example:
<?php
if(isset($_POST['submit'])) {
$string = $_POST['title'];
if ($string == "Ë")
echo "Yes";
else
echo "No";
$vname = str_replace("Ë","AAAA",$string);
echo $vname."<br>";
echo $string;
}
?>
<form method="post" name="Form">
Title: <input name="title" type="text" value="" size="20"/>
<input name="submit" type="submit" value="submit"/>
</form>
Any help would be great!!

Answer 1

Most likely your characterset is wrong. I would suggest sending the following header when outputing html:
<?php header("content-type: text/html; charset=utf-8"); ?>
Where the charset match the charset you are storing your file in.
Edit: Just some more information. The file you store is in one charset for example latin1, while your browser interprets your html page as another charset (utf-8 for example). When the browser then sends the Ë character, it will send the utf-8 code 0xc38b, while the same character is 0xcb. As you can see, these does not match.
Edit - You can also update the CHARSET via HTML5 or xHTML:
HTML5
<meta charset="UTF-8"/>
xHTML
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />